Scientific Name:
Cirsium arvense
Pronunciation:
SUR-see-um ar-VEN-see
Common Name:
Canada thistle
Family Name:
Asteraceae
Plant Type:
Herbaceous perennial, Invasive plant, Weed (horticultural)
Key ID Features:
Perennial weed with rhizomes and nearby plantlets; stem leaves alternate, most oblong, 10-18cm long x 3-7cm wide, irregularly pinnately lobed with spines on margins, white pubescence on under sides; stems are spineless; heads unisexual, male florets 12-14mm long, female florets 22-26mm long, pink to purple, tubular; achenes 2.5-4mm long. E-FloraBC
Habit:
Stiffly upright
Form:
Oval - vertical
Texture:
Medium
Mature Height:
0.7 - 1.3m
Mature Spread:
1.0 - 1.5m
Growth Rate:
Fast
Origin:
Central / west Asia, Europe
Hardiness Rating:
Zone 4: (-34 to -29 °C)
Exposure:
Full sun
Soil/Growing Medium:
Rocky or gravelly or dry
Water Use:
High
Landscape Uses:
Attract birds, Wildlife food
Additional Info:
Google. Noxious weed. Compare to C. vulgare.
Leaf Morphology:
Form:
Simple, Lobed
Arrangement:
Alternate
Texture/Venation:
Prickly
Surfaces:
Pubescent
Shapes:
Oblong
Apices:
Acuminate
Bases:
Decurrent
Margins:
Pinnately lobed, Pectinate, Spinose
Inflorescence Type:
Head (capitulum)
Flower Morphology:
Flowers perfect
Corolla Shape:
Tubular
Ovary Position:
Inferior
Colour (petals):
Violet, Purple, Pink
Flower Scent:
None
Flower Time at Peak:
Jun, Jul, Aug
Fruit Type:
Achene
Fruit Colour:
Brown
Fruiting Time:
Aug, Sep
Bark or Stem Colour:
Organ Modifications:
Prickles, Rhizomes
Propagation:
Seed, Division - below ground parts
Pest Susceptibility:
(Drought tolerant)
